Telephone-receiver



(No Model.)

W. S. CORWIN. TELEPHDNE RECEIVER.

NOQIlELGSLl. Patented May 5,1891.

Farma/mf# Mag/mf. i

UNITED STATES Frioul WILLIAM S. CORXVIN, OF NEVARK, NEV JERSEY.

TELEPHONE-RECEIVER.

SPECIFICATION forming part Of Letters Patent No. 451,634, dated May, 1891.

' Application led November 30, 1888. Serial No. 292,257. (No model.)

be a full, clear, and exact description of theK invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

The object of this invention is to more perfectly transmit and receive articulate speech through an electrical conductor to a distant station, toprovidea moresensitive and efficient receiver, and to work over longer distances with a clearer and louder result than heretofore; also, to provide a durable, convenient, and reliable telephone-receiver and to reduce the cost of manufacture.

The invention consists in an improved telephone-receiver and in the arrangement and combination of parts, substantially as Will be hereinafter set forth, and finally embodied in the claims.

Referring to the accompanying drawings, in which like letters represent corresponding parts in each of the several figures, Figure l represents a top view of a receiver embodying my improvements; Fig. 2, a side view of the same; and Fig. 3, a sectional View showing the internal arrangement of parts, as will be hereinafter more fully described.

In said drawings, a represents a funnelshaped piece, which can be made of any nonmagnetic material, but preferably of hard rubber, and is designed to be threaded at the lower edge Z), so that it may be readily removed from the part g of the receiver. Said funnel-shaped piece d is provided with a hole d in the lower part of the center portion e, so that the vibrations of the diaphragm f directly thereunder may be readily transmitted to the ear whenheld at the top of the said funnel-shaped piece.

g represents a hollow steel tube, preferably 5o flaring at the top portion to provide a resonance-chamber 7o. Said outer tube is a permanent magnet. On top of said tube g and held in place by the shoulder j of the funnelshaped piece d rests a diaphragm f, preferably of thin sheet-iron, although it may be made of steel and magnetized, as will behereinafter set forth. In the center of said steel tube g is inserted a rod of soft iron c, provided with a bobbin of iine wire m at the top end. Said rod c is held in place by guides n and o, made of a non-magnetic substance, as hard rubber. Thus the soft-iron center rod has no metallic connection with the permanently-magnetic case. Both guides are provided with holes p, through which the terminal wires of the bobbin m may pass and be connected to the binding-posts q. Through the center of the lower guide o passes an adj ustment-screw r, which is threaded into the lower end of the rod c. A spring s is placed around said screw r and between the bottom of the rod c and the top of the guide o, so as to force said rod upward and keep it in place. Vhen the screw r is turned, the rod c is raised or lowered, and thus brought nearer to or farther away from the diaphragm f. By

this means a tine adjustment may be secured.

The steel tube g is magnetized, and the diaphragm f, resting upon the top of said tube, if it be of soft iron, is also magnetized by induction. Thus a strong magnetic field free to vibrate extends throughout the resonancechamber 7o. Said magnetic field is also concentrated toward the point t by the influence of the rod of iron c, so that the bobbin m rests in the strongest lines of magnetic force of said magnetic field. Then the sound-waves strike the diaphragm f, producing vibration, the whole magnetic iield is moved and cuts the convolutions of wire in the bobbin m, thus producing electrical currents therein. These currents are probably of an alternating nature. Thus when said vibration is being produced in the receiver at the other end of the line its magnetic field and magnetized diaphragm are being acted upon by either a north or a south pole produced in its iron core by the electrical currents traversing its bobbin of wire, as will be understood. On

the other hand, if said diaphragm be acte( wo upon by a current of varying intensity, then the same result is produced at the receivingstation by its iron eore and bobbin of wire pulling with greater or less intensity upon the magnetic field and magnetized diaphragm, thus producing vibrations.

Having thus fully described my invention, what I claim as new is 1. The improved telephone-receiver oombining therein a permanentlymagnetized steel easing or tube, a soft-iron eore or eenter rod insulated therefrom at its rear end, a diaphragm, the bobbin on, and connecting means, all arranged and adapted to operate substantially as and for the purposes set forth.

2. The improved telephone-receiver combining therein the steel tube g, flaring at its front or open end and permanently magnetized, a vibratory diaphragm resting on the ends thereof, a funnel-shaped piece screwed on said end and holding said diaphragm in position, a soft-iron rod e, arranged centrally in said magnetic tube and held away there from by non-metallic bearings, the said rod extending forward closely adjacent to the said vibratory diaphragm, a spool or bobbin of Wire arranged on said rod or core near said diaphragm, and conducting-Wires and connect-ions, all arranged and combined substantially as and for the purposes set forth.

8. The improved telephone-receiver oombining therein the permanently-magnetic steel tube g, a funnel-shaped end pieee secured thereto, a Vibratory diaphragm secured to said magnet just back of said funnel shaped piece, a central longitudinal rod of soft iron held in said tube by non-metallic bearings, a Wire spool or bobbin m., and oondueting-wires and connections, all said parts being arranged and combined substantially as and for the purposes set forth.

In testimony that I claim the foregoing I have hereunto set my hand this lst day of November, 1883.

WM. S. CORWIN.

Witnesses:

JOHN F. Bann, HENRY REUi-IL. 

